In this study we will investigate factors affecting the central growth of developing retinal axons in both pigmented and albino embroyonic ferret eyes. We shall examine the distribution of retinal axons within extracellular spaces in the marggnal neuroepithelium of the optic cup and adjacent optic stalk. We will determine, using ultrastructural morphological criteria, the role glial elements in forming the walls of these extracellular spaces, thereby serving as a substrate for retinal axon growth. In addition we shall examine the distribution of pioneer retial axons within the marginal neuroepithelium of the optic cup and stalk with respect to the distribution of pigment in the adjacent retinal pigment epithelium of pigmented ferret embryonic eyes during earyly eye development. Comparisons will be made with these results and the results obtained from similarly staged albino ferret embryos in order to determine the potential role pigment plays in guidance of outgrowing.